20826-80-6Relevant academic research and scientific papers
Theoretical studies on the addition of polymetallic lithium organocuprate clusters to acetylene. Cooperative effects of metals in a trap-and-bite reaction pathway
Nakamura, Eiichi,Mori, Seiji,Nakamura, Masaharu,Morokuma, Keiji
, p. 4887 - 4899 (1997)
Ab initio and density functional theoretical investigations into the nature of the reaction of acetylene with noncluster organocuprate reagents, MeCu, Me2Cu-, and lithium organocuprate cluster reagents, Me2CuLi, Me2-CuLi·LiCl, and (Me2CuLi)2 were carried out, and the function of the mixed metal cluster was probed. Intermediates transition structures (TSs) as well as the structures on the intrinsic reaction coordinate in the C-C bond forming stage of the reaction of lithium cuprate clusters have been calculated with the ab initio method (MP2) and density functional method (B3LYP) using all-electron basis sets for copper. The addition reaction of the simple organocopper reagent, MeCu, can be viewed as a simple four-centered addition reaction consisting of nucleophilic addition of an anionic methyl group, while the addition of the cuprate reagent, Me2Cu-, involves transfer of negative charge to the acetylene via the copper atom. In the cluster reaction of Me2CuLi·LiC1, the lithium atom in the cluster stabilizes the developing negative charge on the acetylene moiety and assists the electron flow from the copper atom. Reductive elimination of the transient Cu(III) species initially gives a 1- propenyllithuim-like structure intermediate (nonstationary point), which then undergoes intramolecular transmetalation to give the final product. 1-propenylcopper. Essentially the same mechanism operates also with Me2CuLi and (Me2CuLi)2, indicating that the Li-Me-Cu-Me moiety incorporated in the mixed organocuprate cluster is essential for the reaction. Experiments showed that the strong solvation of the lithium atom with a crown ether, which sequesters the lithium cation from the cluster, strongly decelerates the carbocupration reaction. Thus, theory and experiments revealed the cooperative function of lithium and copper atoms in the cuprate reactions.
The reaction of iodine with vinyltrialkylborates derived from trialkylboranes and trisylhydrazones of methyl ketones. A new method for synthesis of 1,1-dialkylethenes
Avasthi, Kamlakar,Baba, Tsutomu,Suzuki, Akira
, p. 945 - 946 (1980)
1,1-Dialkylethenes are readily prepared in good yields from vinyltrialkylborates derived from trialkylboranes and trisylhydrazones of methyl ketones by treatment with iodine.
α-Sulfinyl Carbanions as a New Source of Olefins
Abramovitch, Adi,Varghese, Jos P.,Marek, Ilan
, p. 621 - 623 (2004)
(Matrix presented) Secondary α-lithiosulfinyl carbanions react either intermolecularly, after transmetalation into an organocopper derivative in an SN2-type process with zinc carbenoid, or intramolecularly via higher-order zincate to give, through a tandem zinc homologation-β- elimination reaction the corresponding alkenes. α,α-Disubstituted alkenes are only formed from tertiary α-lithiosulfinyl carbanions via the 1,2-metalate rearrangement.
Electrochemical fluorosulfonylation of alkenes to access vicinal fluorinated sulfones derivatives
Zhao, Bin,Pan, Zichen,Zhu, Anqiao,Yue, Yanni,Ma, Mengtao,Xue, Fei
supporting information, (2022/01/24)
Herein, we report a practical and efficient fluorosulfonylation of the various alkenes with sulfonyl radical sources (RSO2NHNH2) and Et3N·3HF as cost-effective fluorination reagents under mild conditions. Remarkably, this
Recyclable and reusable PdCl2(PPh3)2/PEG-400/H2O system for the hydrophenylation of alkynes with sodium tetraphenylborate
Liu, Rong,Zhang, Tingli,Huang, Bin,Cai, Mingzhong
, p. 172 - 178 (2020/07/04)
A stable and efficient PdCl2(PPh3)2/PEG-400/H2O catalytic system for the hydrophenylation reaction of alkynes has been developed. In the presence of 3 mol% PdCl2(PPh3)2 and 2 equiv. of HOAc, the hydrophenylation of both terminal and internal alkynes with sodium tetraphenylborate proceeded smoothly in a mixture of PEG-400 and water at room temperature or 50 °C to afford a variety of phenyl-substituted alkenes in moderate to high yields. The isolation of the products was easily performed by extraction with petroleum ether, and the PdCl2(PPh3)2/PEG-400/H2O system could be readily recycled and reused six times without apparent loss of catalytic activity.
Visible-Light-Induced Meerwein Fluoroarylation of Styrenes
Tang, Hai-Jun,Zhang, Bin,Xue, Fei,Feng, Chao
supporting information, p. 4040 - 4044 (2021/05/26)
An unprecedented approach for assembling a broad range of 1,2-diarylethane derivatives with fluorine-containing fully substituted carbon centers was developed. The protocol features straightforward operation, proceeds under metal-free condition, and accommodates a large variety of synthetically useful functionalities. The critical aspect to the success of this novel transformation lies in using aryldiazonium salts as both aryl radical progenitor and also as single electron acceptor which elegantly enables a radical-polar crossover manifold.
Intermolecular [4 + 2] process of N-acyliminium ions with simple olefins for construction of functional substituted-1,3-oxazinan-2-ones
Han, Xiaoli,Nie, Xiaodi,Feng, Yiman,Wei, Bangguo,Si, Changmei,Lin, Guoqiang
supporting information, p. 3526 - 3530 (2021/06/12)
An efficient approach to functionalized 4,6-disubstituted-and 4,6,6-trisubstituted-1,3-oxazinan-2-ones skeleton has been developed through the reaction of semicyclic N,O-acetals 4a and 4b with 1,1-disubstituted ethylenes 5 or 8. As a result of such a [4 +
Cobalt(II)-Catalyzed Stereoselective Olefin Isomerization: Facile Access to Acyclic Trisubstituted Alkenes
Zhang, Sheng,Bedi, Deepika,Cheng, Lu,Unruh, Daniel K.,Li, Guigen,Findlater, Michael
supporting information, p. 8910 - 8917 (2020/12/23)
Stereoselective synthesis of trisubstituted alkenes is a long-standing challenge in organic chemistry, due to the small energy differences between E and Z isomers of trisubstituted alkenes (compared with 1,2-disubstituted alkenes). Transition metal-catalyzed isomerization of 1,1-disubstituted alkenes can serve as an alternative approach to trisubstituted alkenes, but it remains underdeveloped owing to issues relating to reaction efficiency and stereoselectivity. Here we show that a novel cobalt catalyst can overcome these challenges to provide an efficient and stereoselective access to a broad range of trisubstituted alkenes. This protocol is compatible with both mono- and dienes and exhibits a good functional group tolerance and scalability. Moreover, it has proven to be a useful tool to construct organic luminophores and a deuterated trisubstituted alkene. A preliminary study of the mechanism suggests that a cobalt-hydride pathway is involved in the reaction. The high stereoselectivity of the reaction is attributed to both a π-πstacking effect and the steric hindrance between substrate and catalyst.
Stereoselective Synthesis of Vinylcyclopropa[ b]indolines via a Rh-Migration Strategy
Guo, Pan,Sun, Wangbin,Liu, Yu,Li, Yong-Xin,Loh, Teck-Peng,Jiang, Yaojia
supporting information, p. 5978 - 5983 (2020/08/05)
A mild rhodium catalytic system has been developed to synthesize vinylcyclopropa[b]indolines through cyclopropanation of indoles with vinyl carbenoids generated from ring opening of cyclopropenes in situ. By employing a Rh-migration strategy, the products can be obtained with good to excellent E:Z ratios (≤99:1) and complete diastereoselectivity (≤99:1). This method is easy, has a low catalyst loading, and works for a broad range of functionalities.
Palladium-catalyzed double-bond migration of unsaturated hydrocarbons accelerated by tantalum chloride
Murai, Masahito,Nishimura, Kengo,Takai, Kazuhiko
, p. 2769 - 2772 (2019/03/23)
The operationally simple palladium-catalyzed double-bond migration without heteroatom-containing coordinating functional groups is described. Addition of TaCl5 as a second catalyst greatly enhanced the migration efficiency to provide β-alkylsty
